Analysis of the Correlation between Eating Away from Home and BMI in Adults 18 Years and Older in China: Data from the CNNHS 2015.

The purpose of this study is to examine the relationship between the frequency of eating away from home (EAFH) and Body mass index (BMI) in adults. The data were collected from 2015 China Adult Chronic Disease and Nutrition Surveillance (CNNHS 2015). Adults aged 18 and above who had complete dietary frequency questionnaire data were recruited as the research objects. The frequency of EAFH among different genders and BMI groups were compared, and multiple linear regression method was used to analyze the correlation between frequency of EAFH and BMI of adults aged 18 years and above with different gender, age, family per capita annual income, education level, marital status, and occupation level. The frequency of EAFH was higher for adults aged 18-44, eastern region, urban, family per capita annual income of 20,000 RMB or more, highly educated, unmarried, school students, employed people, and obese adults, which were 3.64, 3.30, 3.71, 4.30, 5.92, 5.64, 9.29 and 2.68 times per week, respectively. The highest frequency of EAFH was obese men in urban areas aged 18-44 years, which was 5.63 times per week. Multiple linear regression analysis showed that the frequency of EAFH for breakfast was not associated with BMI ( > 0.05), the frequency of EAFH for lunch was negatively correlated with BMI ( = -0.024, = 0.008), and the frequency of EAFH for dinner was positively correlated with BMI ( = 0.040, = 0.004).The frequency of EAFH of male ( = 0.013, = 0.008), 60 years old and above ( = 0.022, = 0.021), family per capita annual income less than 10,000 RMB ( = 0.019, = 0.005), junior high school education or below ( = 0.012, = 0.009), and unemployed/retired ( = 0.029, = 0.003) adults were positively correlated with BMI. While for women, the frequency of EAFH ( = -0.019, = 0.001) was negatively correlated with BMI. In terms of frequency of EAFH for breakfast, female ( = 0.027, = 0.041), people aged 45-59 years ( = 0.042, = 0.002), aged 60 and above ( = 0.047, = 0.017), eastern China ( = 0.034, = 0.010), junior high school education or below ( = 0.045, = 0.001), married/cohabiting ( = 0.024, = 0.008) adults' frequency of EAFH for breakfast of was positively correlated with BMI. In terms of frequency of EAFH for lunch, female ( = 0.056, = 0.001), people aged 45-59 years ( = 0.024, = 0.005), eastern China ( = 0.034, = 0.004), rural areas ( = 0.035, = 0.006), moderate and high family per capita annual income ( = 0.043, = 0.007; = 0.029, = 0.039), high education level ( = 0.039, = 0.034), married/cohabiting ( = 0.028, = 0.001), on-the-job personnel ( = 0.033, = 0.001) frequency of EAFH for lunch were negatively correlated with BMI. In terms of the frequency of EAFH for dinner, the frequency of EAFH for dinner had a significant positive influence on the BMI of males ( = 0.061, = 0.001). The frequency of dinner EAFH for 18-44 years old ( = 0.042, = 0.028), central region ( = 1.000, < 0.001), rural areas ( = 0.055, = 0.013), married/cohabiting ( = 0.048, = 0.001), on-the-job personnel ( = 0.037, = 0.035) adults were positively correlated with BMI. The frequency of EAFH in urban obese men aged 18-44 was the highest. The frequency of EAFH for breakfast was not correlated with BMI, the frequency of EAFH for lunch was negatively correlated with BMI, and the frequency of EAFH for dinner was positively correlated with BMI. The analysis between EAFH according to the current definition and health-related outcomes is mixed. It is suggested that relevant authorities redefine EAFH from the perspective of health outcomes.